Every year the geriatric population of the United States suffer 200,000 to 300,000 hip fractures. Up to 35 percent of such patients die within the first 12 months after the fracture, and 25 to 35 percent are permanently disabled. Most cases of hip fracture involve a fall and impact to the lateral thigh and trochanteric region of the femur. Falling is common after age 70 due to neuromuscular disease, cerebrovascular disease, and cardiac disease with syncopal episodes or attacks of dizziness. Furthermore, disorders such as Parkinson's Disease, Alzheimer's Disease, and stroke are associated with high annual incidence of falls and hip fractures.
At particular risk for serious hip injury resulting from falls are post-menopausal women and elderly men. This is because the trochanteric region of the femur at the hip area of elderly patients is weakened by osteoporosis and, more rarely, osteomalacia. Women lose bone mass at a rate of 1 percent per year after menopause until age 70, and then the rate of bone loss declines. Men have 20 percent more bone mass at age 40 than women, and lose bone more gradually as they age. Thus, as an individual ages the trochanteric region of the proximal femur and femoral neck become vulnerable to fracture when the individual falls laterally from a standing position to a hard surface.
The trochanteric region of the femur in elderly patients protrudes above surrounding atrophic gluteal and other hip region muscles. This protuberant trochanteric region is a vulnerable impact site when a potential fracture victim falls on his or her side. Thus, a protective device which dissipates the high localized forces imparted to the body of the wearer falls on the hip or trochanteric region may reduce the number and/or severity of hip fractures. Accordingly, it is desirable to provide a protective device which can be worn comfortably by elderly persons and which will significantly reduce the impact force to the trochanteric region of the wearer during a fall thereby decreasing the likelihood of serious hip or femur injury upon a fall from a standing position.
Prior hip protection arrangements have been shown to be insufficient in dissipating and/or absorbing a significantly high percentage of the peak impact force to the hip area associated with a fall. However, one of the most significant problems associated with previous hip protection systems is low patient compliance. Patient compliance is the degree to which the patient follows medical advice about wearing a hip protection device, typically maximizing use of protection devices is recommended. Low patient compliance has been attributed to bulkiness of the device, discomfort over prolonged periods of use, and generally poor aesthetic appearance.
Accordingly, there is a need for a protective device suitable for use by elderly persons which is comfortable to wear for extended periods (including periods of lying down and/or sleep) and provides good aesthetic appearance while still providing sufficient protection to the hip area to prevent significant injury thereto upon a fall from a standing position. Such protective devices disclosed below and claimed herein is a significant improvement over protective devices having a rigid outer shield as described in U.S. Pat. No. 5,636,377 and Wiener et al., “Force Reduction by an External Hip Protector on Human Hip after Falls,” Clin. Orthopaedics & Related Res., 398, 157-168 (2002), both of which are hereby incorporated by reference. Those references teach a protective pad having a rigid outer shield formed of thin layer of a rigid material such as a suitable plastic, one or more layers of shock absorbing resilient material affixed to the inside, and a concave surface of the rigid outer shield, such as rubber foam. The improvement aims to increase the dissipation of force to over 80 percent, and preferably over 90 percent, of the impact force per square inch to the trochanteric region realized from a lateral fall from a standing position. The improvement also increases patient compliance with a protective device lacking a substantially rigid component, such as a rigid shield. The improvement also provides an inner layer of polymeric material, directly adjacent to the hip region, which is soft and comfortable.